1 Field of the Invention:
This invention relates to a method of removing adhering particles from the surface of the running web and an apparatus for carrying out the method and, more specifically, to a method of and apparatus for removing dust from a photosensitive material running web prior to applying the photosensitive emulsion thereto.
2 Description of the Prior Art:
In accordance with the usual techniques for applying emulsion on a moving plastic film, paper and the like, it has been known to employ a doctor blade method, bead method and the like. In the doctor blade method, the dust adhering to the back surface of the web causes white spots on the photosensitive films. In the bead method, the dust adhering on the surface of the web causes unevenness in thickness and scratches or streaks formed on the surface of the applied emulsion which are serious imperfections in the applied emulsion layer. The present invention prevents the above described imperfections in applying emulsion on the web by removing the dust from the front and back surfaces of the running web.
Heretofore, it has been proposed to remove the dust from the running web by utilizing air blow, air suction, brushing, direct removal with a knife or a doctor blade, attraction of static electricity, or a combination of the above, and the like. However, these methods of removing dust involve certain disadvantages, such as low removal effects, adhering flocks from the brush, the generation of scratches, and the like. Accordingly, there has been no adequate method of removing the dust adhering to the web which sufficiently removes the same prior to the final production of the photosensitive film without major disadvantages.
It has also been known in the art to wash the web in water in order to remove the dust adhering to the web. However, this method is disadvantageous, first in that the undercoated layer may be humidified and affected chemically by the water unless the water is quickly and thoroughly dried from the web and, second, in that it causes the generation of hills and valleys in the emulsion layer unless all the water has been dried from the web before the emulsion layer is applied. Another disadvantage inherent in the use of the method just described is that such equipment occupies a large area of a plant and is large and complicated.